This section is intended to introduce various aspects of the art, which may be associated with exemplary embodiments of the present disclosure. This discussion is believed to assist in providing a framework to facilitate a better understanding of particular aspects of the present disclosure. Accordingly, it should be understood that this section should be read in this light, and not necessarily as admissions of prior art.
Field of the Invention
The present disclosure relates to the field of well completions. More specifically, the present invention relates to the isolation of formations in connection with wellbores that have been completed through multiple zones using sand control devices. This application also relates to sand screen assemblies that have both bypass conduits for gravel slurry, and in-flow control devices for controlling the flow of production fluids into a base pipe, thereby providing for both a consistent gravel packing and the control of production fluids along the wellbore.
Discussion of Technology
In the drilling of oil and gas wells, a wellbore is formed using a drill bit that is urged downwardly at a lower end of a drill string. After drilling to a predetermined depth, the drill string and bit are removed and the wellbore is lined with a string of casing. An annular area is thus formed between the string of casing and the formation. A cementing operation is typically conducted in order to fill or “squeeze” the annular area with cement. The combination of cement and casing strengthens the wellbore and facilitates the isolation of formations behind the casing.
It is common to place several strings of casing having progressively smaller outer diameters into the wellbore. The process of drilling and then cementing progressively smaller strings of casing is repeated several times until the well has reached total depth. The final string of casing, referred to as a production casing, is cemented in place and perforated. In some instances, the final string of casing is a liner, that is, a string of casing that is not tied back to the surface.
As part of the completion process, a wellhead is installed at the surface. The wellhead controls the flow of production fluids to the surface, or the injection of fluids into the wellbore. Fluid gathering and processing equipment such as pipes, valves and separators are also provided. Production operations may then commence.
It is sometimes desirable to leave the bottom portion of a wellbore open. In open-hole completions, a production casing is not extended through the producing zones and perforated; rather, the producing zones are left uncased, or “open.” A “slotted base pipe” is then positioned inside the open wellbore extending down below the last string of casing.
There are certain advantages to open-hole completions versus cased-hole completions. First, because open-hole completions typically have no perforation tunnels, formation fluids can converge on the wellbore radially 360 degrees. This has the benefit of eliminating the additional pressure drop associated with converging radial flow and then linear flow through particle-filled perforation tunnels. The reduced pressure drop associated with an open-hole completion virtually guarantees that it will be more productive than an unstimulated, cased hole in the same formation.
Second, open-hole techniques are oftentimes less expensive than cased hole completions. For example, the use of slotted base pipes eliminates the need for cementing, perforating, and post-perforation clean-up operations. Alternatively, the use of a sand screen, with or without a gravel packs along the open hole wellbore, helps maintain the integrity of the wellbore while allowing substantially 360 degree radial formation exposure.
In connection with the installation of gravel packs, fluid bypass technology has been developed to ensure a uniform installation of “gravel pack” along the length of sand screens. This bypass technology employs shunt tubes, or alternate flow channels, placed along selected lengths of sand screen joints. The tubes allow a gravel slurry to be transported downhole across premature sand bridges and even packers along a wellbore. Such fluid bypass technology is described, for example, in U.S. Pat. No. 5,588,487 entitled “Tool for Blocking Axial Flow in Gravel-Packed Well Annulus,” and PCT Publication No. WO2008/060479 entitled “Wellbore Method and Apparatus for Completion, Production, and Injection,” each of which is incorporated herein by reference in its entirety.
Additional references which discuss alternate flow channel technology include U.S. Pat. Nos. 7,971,642; 7,938,184; 7,661,476; 8,011,437; 8,186,429; 8,215,406; 8,430,160; and 8,789,612. See also M. T. Hecker, et al., “Extending Openhole Gravel-Packing Capability: Initial Field Installation of Internal Shunt Alternate Path Technology,” SPE Annual Technical Conference and Exhibition, SPE Paper No. 135,102 (September 2010); and M. D. Barry, et al., “Open-hole Gravel Packing with Zonal Isolation,” SPE Paper No. 110,460 (November 2007). The alternate flow channel technology enables a true zonal isolation in multi-zone, open hole gravel pack completions. The alternate flow channel technology is practiced under the name Alternate Path®, owned by ExxonMobil Corporation of Irving, Tex.
Recently, improvements to the alternate flow channel technology have included the use of inflow control devices placed strategically along sand control assemblies. The inflow control devices serve as restrictive flow paths. The inflow control devices, or “ICD's,” beneficially balance the inflow profile of hydrocarbon fluids along a sand control assembly. ICD's further help prevent gas/water breakthrough. Problems associated with water/gas production may include productivity loss, equipment damage, and/or increased treating, handling and disposal costs at the surface. These problems are further compounded for wells that have a number of different completion intervals and where the formation pressure may vary from interval to interval. As such, water or gas breakthrough in any one of the intervals may threaten the remaining reserves within the well.
International Publ. No. WO 2007/126496; U.S. Pat. Nos. 7,708,068; 7,984,760; 8,127,831; and U.S. Patent Publ. No. 2015/0027700 disclose a variety of embodiments for using in-flow control devices, including in connection with sand screens. These include the use of swellable or degradable material and sliding sleeves, which may be actuated or manipulated to block the flow of production fluids into a base pipe once production operations commence. Thus, selective fluid flows along one or more joints of sand screen, particularly during production mode, may be accomplished using in-flow control devices.
It is observed that the use of ICD's as described in International Publ. No. WO 2007/126496 and other disclosures is applicable for both conventional sand screens and Alternate Path® screens. However, additional fluid flow control hardware is needed for modern sand screen arrangements having Internal Shunt Alternate Path® (ISAPT) technology, wherein coupling assemblies for connecting shunt tubes along sand screens are used. These include the sand control devices and connection hardware described in International Publ. No. WO2008/060479 and in U.S. Pat. No. 8,356,664.
Therefore, a need remains for an improved sand control assembly that provides bypass technology during a gravel packing procedure, and which also offers flow control between a base pipe and a surrounding annular region during production operations through the use of in-flow control devices or valves. Additionally, a need exists for a method of completing a wellbore wherein a sand screen assembly is placed along a formation that uses selected or controlled fluid communication between the sand screen and the bore of the base pipe during both gravel packing and production.